The objective of this application is to establish the effect of perinatal metabolic and hormonal imprinting upon hypothalamic mechanisms regulating appetite. Aim 1 is to examine the immediate and long-term effects of postnatal ICV administration of NPY or antisense NPY oligonucleotide. Aim 2 is to examine the immediate and long-term effects of postnatal systemic or ICV administration of insulin and insulin antibody. Aim 3 is to investigate the postnatal systemic administration of glucose. Aim 4 is to study the postnatal systemic administration of glucocorticoids on NPY and CRF levels and receptors.